Question

A favorable energetic process has an overall negative Gibbs free energy change (ΔG). As a protein folds, amino acid chains can have weak, yet attractive intermolecular interactions that result in a more ordered molecule. What other entropic process occurs at the same time to balance the unfavorable entropic contribution from the more ordered protein?

Answer 1

The process that balance the the unfavourable entropic contribution from protein folding is the rearrangement of the water molecules around it.

Step-by-step explanation:

Proteins are often in aqueous solutions. And around the protein, the water molecules are distributed in the way thermodynamically most favorable. So, the water molecules interact with the aminoacidic residues of the protein, making posible for the macromolecule to exist in solution.

During protein folding, are formed several interactions among the aminoacidic residues, which are responsible for the structure the protein adopts.

At the beginning it might seem this process shouldn't be possible, as the transition from one state to another more ordered one isn't spontaneous.

But as these new interactions are formed, an enormous amount of water molecules that were interacting with the protein are "released", being able to adopt several more configurations, in other words, gaining entropy.

In summary, the reduced entropy from the protein folding is balanced by the gain in entropy by the water molecules in the surrounding medium, which allows the process to occur.